This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Tuberculosis (TB) is the current leading cause of death for AIDS patients. Its pathogen, Mycobacterium tuberculosis, infects one-third of the world population. Cell wall lipids are essential for the survival, virulence and latency development of M. tuberculosis. Three acyl-CoA carboxylases (ACCases), AccD4, AccD5 and AccD6, are important for cell wall lipid biosynthesis, whose disruption leads to pathogen death. The lack of ACCase crystal structures has greatly hampered the drug design effort of new tuberculosis drugs that target at ACCase. SSRL beam time to solve crystal structures of multi-subunit ACCase will be scientifically significant, because it will lead to the first ever multi-subunit ACCase complex crystal structure, and help define the biological roles of AccD4-6. Its medical significance lies in structure-based drug screening based on ACCase crystal structures.